Kolkata metro railway has initiated a major upgrade of its systems on the Blue Line, aiming to enhance passenger amenities, operational efficiency and overall safety across the 41 year old corridor that runs between Dakshineswar and Sahid Khudiram.
A Metro spokesperson said on Saturday that seven additional traction substations will be set up at Kalighat, Netaji Bhawan, Maidan, Esplanade, MG Road, Sovabazar Sutanuti and between Belgachia and Shyambazar stations.
With their commissioning, the Blue Line will have traction substations at every station, similar to the Purple Line from Joka to Majerhat and the Orange Line from Kavi Subhas to Beleghata.
"Apart from this, in order to meet the demand for additional traction power with fire safety, an order for two Traction SubStations (TSS) at Chandni Chowk and Geetanjali (Naktala) has already been placed. The TSS coming up at Chandni Chowk will help avoid congestion of rakes between Esplanade and Central stations," he said.
Upgrades are underway for the ventilation and cooling system of stations and tunnels.
"In the 41-year-old existing system, tunnels were also cooled as the rakes were non-air conditioned. But as Metro Railway, Kolkata is now armed with all AC rake fleet, discarding the non AC rakes, it provides the opportunity to shift to TVS (Tunnel Ventilation System) to have the state-of-the-art smoke extraction system as well," he said.
The existing network uses forced ventilation through centrifugal fans of 110 kW at fourteen midpoints, which operate round the clock.
"These fans used to consume energy incurring a cost of Rs 21 crore annually. By installing Variable Frequency Drive in midpoint in 2021-2022 this consumption was reduced by half. These fans can rotate in one direction to work as exhaust fans," the spokesperson said.
All the old fans will now be replaced by axial fans capable of two hour operation even when handling air heated up to 250 degrees Celsius.
These fans will be triggered automatically in the event of fire or smoke inside the tunnel or if the ambient temperature, CO2 concentration or sub soil temperature crosses prescribed limits.
"A work order has already been placed on the Indian subsidiary of a Japanese company for upgrading Blue Line's stations Environmental Control Systems (ECS) and upgrade the TVS. This holding company has already commissioned ECS and TVS systems in more than one hundred underground Metro stations in Singapore. A team of Japanese engineers has already visited Jatin Das Park station air conditioning plant and other areas," he said.
The spokesperson said the ongoing upgrade will improve fire safety, lower electricity bills and reduce carbon emissions by 12,300 metric tonnes every year.